heaviness vs broadness

heaviness and broadness both are nouns.

Word	Noun	Adjective	Verb	Adverb
heaviness	Yes	No	No	No
broadness	Yes	No	No	No

As nouns, broadness is a hypernym of heaviness; that is, broadness is a word with a broader meaning than heaviness:

Other hypernyms of heaviness include wideness.

heaviness (noun)	broadness (noun)
the property of being comparatively great in weight	the property of being wide; having great width
used of a line or mark
unwelcome burdensome difficulty
an oppressive quality that is laborious and solemn and lacks grace or fluency
persisting sadness